I propose to expand our work on a voltage-dependent K ion-selective ion conductance channel from the sarcoplasmic reticulum membrane. The channel protein is inserted into a planar phospholipid membrane and the electrical conductance behavior conferred upon the membrane is studied by voltage-clamp measurements. The channel will be studied via 5 different approaches: (1) steady-state electrical properties, including channel modification by blocking agents and proteolytic enzymes; (2) gating kinetics, including the stochastic behavior of single-channel conductance fluctuations; (3) the mechanism of ion conduction and selectivity in the open channel; (4) assay of the channel in native SR vesicles; and (5) isolation, purification, and functional reconstitution of the channel. I am proposing to increase greatly our capability of performing kinetic experiments by automation of our data acquisition and storage facilities. The overall purpose of this study is to characterize in this quasireconstituted membrane system the electrical behavior of a channel-type inophore from a mammalian membrane which is itself inaccessible to direct electrical study.